Pharmaceutical formulation

ABSTRACT

The invention relates to pharmaceutical formulations, and more particularly to formulations containing cannabinoids for administration via a pump action spray. In particular, the invention relates to pharmaceutical formulations, for use in administration of lipophilic medicaments via mucosal surfaces, comprising: at least one lipophilic medicament, a solvent and a co-solvent, wherein the total amount of solvent and co-solvent present in the formulation is greater than 55% wt/wt of the formulation and the formulation is absent of a self emulsifying agent and/or a fluorinated propellant.

RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.14/074,067, filed Nov. 7, 2013, now U.S. Pat. No. 9,029,423, which is acontinuation of U.S. patent application Ser. No. 13/486,227, filed Jun.1, 2012, now U.S. Pat. No. 8,603,515, which is a continuation of U.S.patent application Ser. No. 12/704,729, filed Feb. 12, 2010, now U.S.Pat. No. 8,211,946, which is a continuation of U.S. patent applicationSer. No. 11/229,052, filed Sep. 16, 2005, now U.S. Pat. No. 7,709,536,which is a continuation of U.S. patent application Ser. No. 10/218,989,filed Aug. 14, 2002, now U.S. Pat. No. 6,946,150, the entire contents ofeach of which are incorporated by reference herein.

FIELD OF THE INVENTION

The present invention relates to pharmaceutical formulations, and moreparticularly to formulations containing cannabinoids for administrationvia a pump action spray.

BACKGROUND OF THE INVENTION

It has long been known to introduce drugs into the systemic circulationsystem via a contiguous mucous membrane to increase onset of activity,potency etc.

For example, U.S. Pat. No. 3,560,625 disclose aerosol formulations forintroducing an alkoxybenzamide into the systemic circulatory system. Twodifferent types of aerosol formulations are disclosed:

a) fluorinated hydrocarbon type comprising 2% by weight alkoxybenzamide,18% ethanol, and 80% propellant; and

b) nebuliser type comprising 0.5% by weight alkoxybenzamide, a mixedsolvent system comprising 10.3% ethanol and 31.4% propylene glycol and57.8% deionised water.

U.S. Pat. No. 3,560,625 identifies a problem in finding a suitablesolvent system to produce an aerosol spray for inhalation of theortho-ethoxybenzamide, due to the fact that whilst ethanol wasundoubtedly the best solvent, a mixture containing more than 18% ofethanol by weight produced an unpleasant oral reaction which more thancounterbalanced the efficacy of the oral route.

When the present applicant set out to produce spray formulations for abotanical drug substance comprising one or more cannabinoids they wereaware that the highly lipophylic nature of the cannabinoids couldpresent problems in formulating the active component(s).

The present applicant first sought to develop a formulation fororomucosal, preferably sublingual, delivery in a pressurised aerosol orspray form, as disclosed in international patent applicationPCT/GB01/01027. Their initial focus was on propellant driven systemswith HFC-123a and HFC-227 but these proved to be unsuitable as solventsfor the cannabinoids. The formulations comprised synthetic Δ9-THC inamounts from 0.164 to 0.7% wt/wt, with ethanol as the primary solvent inamounts up to 20.51% by weight. One particular composition comprised0.164% synthetic Δ9-THC, 4.992% ethanol, 4.992% propylene glycol and89.582% p134a (propellant).

The applicant found that even at ethanol levels of 20% by volume of thetotal formulation volume they were unable to dissolve sufficient levelsof Δ9-THC in a standard spray dose to meet clinical needs, because ofthe cannabinoids poor solubility in the propellant. They also found thatthe ethanol level could not be increased, as the deliverycharacteristics of the device nozzle altered substantially when thelower volatility solvents were increased above a critical ratio. TheHFC-123a and HFC-227 propellant sprays delivered a maximum of 7 mg/ml,whereas initial clinical studies suggested the formulations would berequired to contain up to 50 mg cannabinoids/ml.

Thus, the present applicants focussed on self-emulsifying drug deliverysystems, as are discussed in detail in a review article European Journalof Pharmaceutics and Biopharmaceutics 50 (2000) 179-188, which concludedthat the poor aqueous solubility of many chemical entities represents areal challenge for the design of appropriate formulations aimed atenhancing oral bioavailability.

In their co-pending International application PCT/GB02/00620 theapplicant discloses a wide range of cannabinoid-containing formulationscontaining at least one self-emulsifying agent. The inclusion of atleast one self-emulsifying agent was thought necessary to get theformulation to adhere to the mucosal surface in order to achievesufficient absorption of the cannabinoids. One particular formulationcomprised 2% by wt glycerol mono-oleate, 5% CBME of G1 cannabis to giveTHC, 5% CBME of G5 cannabis to give CBD, 44% ethanol BP and 44%propylene glycol.

SUMMARY OF THE INVENTION

Surprisingly, the applicant has found that they do not absolutelyrequire the presence of a self-emulsifying agent in a liquid formulationto achieve a satisfactory dosage level by oromucosal, and specificallysub-lingual or buccal, application.

Indeed, contrary to the teachings of U.S. Pat. No. 3,560,625 and theEuropean Journal of Pharmaceutics and Biopharmaceutics 50 (2000)179-188, they have been able to produce a simple and effective vehiclefor delivering a lipophilic medicament in a liquid spray.

According to a specific aspect of the present invention there isprovided a pharmaceutical formulation consisting essentially of one ormore cannabinoids, ethanol and propylene glycol.

Preferably the one or more cannabinoids are present in the form of atleast one extract from at least one cannabis plant. The cannabisplant(s) preferably include at least one cannabis chemovar. Mostpreferably the plant extract will be a botanical drug substance (BDS),as defined herein.

Optionally, the formulation may additionally contain a flavour, such as,for example, peppermint oil.

The formulation may also contain, in addition to the cannabinoid(s), afurther active agent, which is preferably an opiate, for examplemorphine. Thus, it is contemplated to provide a formulation consistingessentially of one or more cannabinoids, ethanol, propylene glycol andan opiate, preferably morphine.

A typical liquid pharmaceutical formulation according to this specificaspect of the invention, given by way of example and not intended to belimiting to the invention, may contain in a 1 ml vol: THC 25-50 mg/ml,preferably 25 mg/ml (based on amount of cannabinoid in a botanical drugsubstance), CBD 25-50 mg/ml, preferably 25 mg/ml (based on amount ofcannabinoid in a botanical drug substance), propylene glycol 0.5 ml/ml,peppermint oil 0.0005 ml/ml, and ethanol (anhydrous) qs to 1 ml.

Other preferred formulations include a “high THC” formulation comprisingin a 1 ml vol: THC 25 mg/ml (based on amount of cannabinoid in abotanical drug substance), propylene glycol 0.5 peppermint oil 0.0005ml/ml, and ethanol (anhydrous) qs to 1 ml; and a “high CBD” formulationcomprising in a 1 ml vol: CBD 25 mg/ml (based on amount of cannabinoidin a botanical drug substance), propylene glycol 0.5 ml/ml, peppermintoil 0.0005 ml/ml, and ethanol (anhydrous) qs to 1 ml.

In these formulations the cannabinoids are added as botanical drugsubstances derived from cannabis plants, quoted amounts of cannabinoidscorrespond to total amount (weight) of cannabinoid present in 1 ml ofthe final formulation. The skilled reader will appreciate that the totalamount of BDS which must be added in order to achieve the desired amountof cannabinoid in the final formulation will be dependent on theconcentration of cannabinoid present in the BDS, which will vary betweendifferent batches of BDS.

The finding that such a simple combination of one or more cannabinoids,ethanol and propylene glycol can be used effectively in a pump actionspray was unexpected.

The applicant has found that, where the solvent/co-solvent system isethanol/propylene glycol and the lipophilic medicament comprises one ormore cannabinoids in the form of a botanical drug substance (BDS), thelimits in which the solvent/co-solvent will work effectively are quitenarrow, as discussed below.

More broadly speaking, and according to a general aspect of theinvention, there is provided a liquid pharmaceutical formulation, foruse in administration of a lipophilic medicament via a mucosal surface,comprising at least one lipophilic medicament, a solvent and aco-solvent, wherein the total amount of solvent and co-solvent presentin the formulation is greater than 55% wt/wt of the formulation and theformulation is absent of a self-emulsifying agent and/or a fluorinatedpropellant.

Preferably the amount of solvent/co-solvent is greater than 80%, morepreferably in the order 90-98%.

Preferably the formulation has a water content of less than 5%.

Preferably the formulation does not contain any type of propellant.

The formulation also lacks any self-emulsifying agent. Self-emulsifyingagents are defined herein as an agent which will form an emulsion whenpresented with an alternate phase with a minimum energy requirement. Incontrast, an emulsifying agent, as opposed to a self-emulsifying agent,is one requiring additional energy to form an emulsion. Generally aself-emulsifying agent will be a soluble soap, a salt or a sulphatedalcohol, especially a non-ionic surfactant or a quaternary compound.Exemplary self-emulsifying agents include, but are not limited to,glyceryl mono oleate (esp. SE grade), glyceryl monostearate (esp. SEgrade), macrogols (polyethylene glycols), and polyoxyhydrogenated castoroils e.g. cremophor.

The formulation may additionally comprise a flavouring. The preferredflavouring is peppermint oil, preferably in an amount by volume of up to0.1%, typically 0.05% v/v.

Preferably the solvent is selected from C1-C4 alcohols. The preferredsolvent is ethanol.

Preferably the co-solvent is a solvent which allows a lower amount ofthe “primary” solvent to be used. In combination with the “primary”solvent it should solubilise the lipophylic medicament sufficiently thata medically useful amount of the lipophylic medicament is solubilised. Amedically useful amount will vary with the medicament, but forcannabinoids will be an amount of at least 1.0 mg/0.1 ml ofsolvent/co-solvent.

Preferred co-solvents are selected from glycols, sugar alcohols,carbonate esters and chlorinated hydrocarbons.

The glycols are preferably selected from propylene glycol and glycerol,with propylene glycol being most preferred. The carbonate ester ispreferably propylene carbonate.

The most preferred combination is ethanol as the solvent and propyleneglycol as the co-solvent.

The preparation of liquid formulations for oropharangeal delivery ofcannabinoids poses a number of problems. First, it is necessary todeliver at least 1.0 mg, more preferably at least 2.5 mg and even morepreferably at least 5 mg of cannabinoids per 0.1 ml of liquidformulation to achieve a therapeutic effect in a unit dose. In thisregard a patient may require up to 120 mg cannabinoid/day, on averagearound 40 mg/day to be taken in a maximum of six doses.

In the case of a sublingual or buccal delivery, this means deliveringthis quantity of the active ingredient in an amount of formulation whichwill not be swallowed by the patient, if the active ingredient is to beabsorbed transmucosally.

Whilst such amounts can be achieved by dissolving the cannabinoid inethanol as the solvent, high concentrations of ethanol provoke astinging sensation and are beyond the limit of tolerability.

There is thus a need to use a co-solvent in order to reduce the amountof ethanol, whilst still enabling sufficient quantities of cannabinoidto be solubilised.

The applicant has discovered that the choice of co-solvent is limited.Preferred co-solvents should have a solubilizing effect sufficient toallow enough cannabinoid to be solubilised in a unit dose, namely atleast 1.0 mg/0.1 ml of formulation, and which allows the amount ofsolvent present to be reduced to a level which is within the limits ofpatient tolerability. Particularly suitable co-solvents which fulfilthese criteria are propylene glycol and glycerol.

In a preferred embodiment the total amount of solvent and co-solventpresent in the formulation, is greater than about 65% w/w, morepreferably greater than about 70% w/w, more preferably greater thanabout 75% w/w, more preferably greater than about 80% w/w, morepreferably greater than about 85% w/w of the formulation. Mostpreferably the total amount of solvent and co-solvent present in theformulation is in the range from about 80% w/w to about 98% w/w of theformulation.

In a preferred embodiment the formulations according to the inventionare liquid formulation administered via a pump-action spray. Pump-actionsprays are characterised in requiring the application of externalpressure for actuation, for example external manual, mechanical orelectrically initiated pressure. This is in contrast to pressurizedsystems, e.g. propellant-driven aerosol sprays, where actuation istypically achieved by controlled release of pressure e.g. by controlledopening of a valve.

Pump-action sprays are found to be particularly beneficial when it comesto delivering cannabinoids. Indeed, previously people have focussedtheir attention on solvent systems including a propellant.

Whilst it has been recognised that there are disadvantages with suchsystems, including the speed of delivery, those skilled in the art havetried to address this by slowing the propellant or by altering thenozzle. The applicants have found that by using a pump spray with theirformulations they are able to produce a spray in which the particleshave a mean aerodynamic particle size of between 15 and 45 microns, moreparticularly between 20 and 40 microns and an average of about 33microns. These contrast with particles having a mean aerodynamicparticle size of between 5 and 10 microns when delivered using apressurised system.

In fact, comparative tests by the applicant have shown such apump-action spray system to have advantages in being able to deliver theactive components to a larger surface area within the target area. Thisis illustrated with reference to the accompanying Example 3.

The variation in particle distribution and sprayed area has beendemonstrated by direct experiment. A formulation as described in theaccompanying Example 4 was filled into a pump action spray assembly(Valois vial type VP7100 actuated). The same formulation was filled intoa pressurised container powered by HFA 134a.

Both containers were discharged at a distance of 50 mm from a sheet ofthin paper held at right angles to the direction of travel of the jet.The pattern of spray produced in both cases by discharge of 100 μl wasthen visualised against the light. In both cases the pattern ofdischarge was circular and measurements were as follows:

Mean Diameter (mm) Mean Area (mm²) Pump Action Spray 23 425.5Pressurised Spray 16 201.1

The pressurised spray produced pooling of liquid at the centre of thearea. The pump action spray gave a more even spray pattern and less“bounce back”. There was also a significantly greater area covered bythe pump action spray. The conditions under which this test was carriedout are relevant to the in-practice use of the device. A wider area ofbuccal mucosa can be reached by the pump action spray compared with thepressurised spray.

For pump spray applications the solvent/co-solvent combination must havea viscosity within the viscosity range defined by the preferredsolvent/co-solvent combination. Thus it should be a viscosity rangingbetween that for an ethanol/propylene glycol combination where theethanol/propylene glycol are present in the relative proportions byvolume of 60/40 and 40/60, more preferably still 55/45 to 45/55 and mostpreferably about 50/50.

The viscosity of the resulting formulation when packaged for delivery bypump action through a mechanical pump such as, for example, a VP7actuator valve (Valois), allows the resulting aerosol to deliver a sprayhaving a mean aerodynamic particle size of from 20-40 microns, morepreferably 25-35 and most preferably with an average particle size offrom 30-35 microns. This maximises contact with the target mucosalmembrane for sublingual/buccal delivery.

Preferably the formulations according to the general and specificaspects of the invention comprises as the lipophilic medicament one ormore cannabinoids.

Preferably the lipophilic medicament is at least one extract from atleast one cannabis plant. The cannabis plant(s) preferably include atleast one cannabis chemovar. Most preferably the plant extract will be abotanical drug substance (BDS), as defined herein.

A “plant extract” is an extract from a plant material as defined in theGuidance for Industry Botanical Drug Products Draft Guidance, August2000, US Department of Health and Human Services, Food and DrugAdministration Center for Drug Evaluation and Research.

“Plant material” is defined as a plant or plant part (e.g. bark, wood,leaves, stems, roots, flowers, fruits, seeds, berries or parts thereof)as well as exudates.

The term “Cannabis plant(s)” encompasses wild type Cannabis sativa andalso variants thereof, including cannabis chemovars which naturallycontain different amounts of the individual cannabinoids, Cannabissativa subspecies indica including the variants var. indica and var.kafiristanica, Cannabis indica and also plants which are the result ofgenetic crosses, self-crosses or hybrids thereof. The term “Cannabisplant material” is to be interpreted accordingly as encompassing plantmaterial derived from one or more cannabis plants. For the avoidance ofdoubt it is hereby stated that “cannabis plant material” includes driedcannabis biomass.

In the context of this application the terms “cannabis extract” or“extract from a cannabis plant”, which are used interchangeably,encompass “Botanical Drug Substances” derived from cannabis plantmaterial. A Botanical Drug Substance is defined in the Guidance forIndustry Botanical Drug Products Draft Guidance, August 2000, USDepartment of Health and Human Services, Food and Drug AdministrationCenter for Drug Evaluation and Research as: “A drug substance derivedfrom one or more plants, algae, or macroscopic fungi. It is preparedfrom botanical raw materials by one or more of the following processes:pulverisation, decoction, expression, aqueous extraction, ethanolicextraction, or other similar processes.” A botanical drug substance doesnot include a highly purified or chemically modified substance derivedfrom natural sources. Thus, in the case of cannabis, “botanical drugsubstances” derived from cannabis plants do not include highly purified,Pharmacopoeial grade cannabinoids.

“Cannabis based medicine extracts (CBMEs)”, such as the CBMEs preparedusing processes described in the accompanying examples, are classifiedas “botanical drug substances”, according to the definition given in theGuidance for Industry Botanical Drug Products Draft Guidance, August2000, US Department of Health and Human Services, Food and DrugAdministration Center for Drug Evaluation and Research.

“Botanical drug substances” derived from cannabis plants include primaryextracts prepared by such processes as, for example, maceration,percolation, extraction with solvents such as C1 to C5 alcohols (e.g.ethanol), Norflurane (HFA134a), HFA227 and liquid carbon dioxide undersub-critical or super-critical conditions. The primary extract may befurther purified for example by super-critical or sub-critical solventextraction, vaporisation or chromatography. When solvents such as thoselisted above are used, the resultant extract contains non-specificlipid-soluble material. This can be removed by a variety of processesincluding “winterisation”, which involves chilling to −20° C. followedby filtration to remove waxy ballast, extraction with liquid carbondioxide and by distillation.

In the case where the cannabinoids are provided as a BDS, the BDS ispreferably obtained by CO₂ extraction, under sub-critical orsuper-critical conditions, followed by a secondary extraction, e.g. anethanolic precipitation, to remove a substantial proportion of waxes andother ballast. This is because the ballast includes wax esters andglycerides, unsaturated fatty acid residues, terpenes, carotenes, andflavenoids which are not very soluble in the chosen solvent/co-solvent,particularly the preferred co-solvent, propylene glycol, and willprecipitate out. Most preferably the BDS is produced by a processcomprising decarboxylation, extraction with liquid carbon dioxide andthen a further extraction to remove significant amounts of ballast. Mostpreferably the ballast is substantially removed by an ethanolicprecipitation.

Most preferably, cannabis plant material is heated to a definedtemperature for a defined period of time in order to decarboxylatecannabinoid acids to free cannabinoids prior to extraction of the BDS.

Preferred “botanical drug substances” include those which are obtainableby using any of the methods or processes specifically disclosed hereinfor preparing extracts from cannabis plant material. The extracts arepreferably substantially free of waxes and other non-specific lipidsoluble material but preferably contain substantially all of thecannabinoids naturally present in the plant, most preferably insubstantially the same ratios in which they occur in the intact cannabisplant.

Botanical drug substances are formulated into “Botanical Drug Products”which are defined in the Guidance for Industry Botanical Drug ProductsDraft Guidance, August 2000, US Department of Health and Human Services,Food and Drug Administration Center for Drug Evaluation and Research as:“A botanical product that is intended for use as a drug; a drug productthat is prepared from a botanical drug substance.”

“Cannabis plants” includes wild type Cannabis sativa and variantsthereof, including cannabis chemovars which naturally contain differentamounts of the individual cannabinoids.

The term “cannabinoids” also encompasses highly purified, PharmacopoeialGrade substances, which may be obtained by purification from a naturalsource or via synthetic means. Thus, the formulations according to theinvention may be used for delivery of extracts of cannabis plants andalso individual cannabinoids, or synthetic analogues thereof, whether ornot derived from cannabis plants, and also combinations of cannabinoids.

Preferred cannabinoids include, but are not limited to,tetrahydrocannabinoids, their precursors, alkyl (particularly propyl)analogues, cannabidiols, their precursors, alkyl (particularly propyl)analogues, and cannabinol. In a preferred embodiment the formulationsmay comprise any cannabinoids selected from tetrahydrocannabinol,Δ⁹-tetrahydrocannabinol (THC), Δ⁸-tetrahydrocannabinol,Δ⁹-tetrahydrocannabinol propyl analogue (THCV), cannabidiol (CBD),cannabidiol propyl analogue (CBDV), cannabinol (CBN), cannabichromene,cannabichromene propyl analogue and cannabigerol, or any combination oftwo or more of these cannabinoids. THCV and CBDV (propyl analogues ofTHC and CBD, respectively) are known cannabinoids which arepredominantly expressed in particular Cannabis plant varieties and ithas been found that THCV has qualitative advantageous propertiescompared with THC and CBD respectively. Subjects taking THCV report thatthe mood enhancement produced by THCV is less disturbing than thatproduced by THC. It also produces a less severe hangover.

Most preferably the formulations will contain THC and/or CBD.

In a preferred embodiment the formulations may contain specific,pre-defined ratios by weight of different cannbinoids, e.g. specificratios of CBD to THC, or tetrahydrocannabinovarin (THCV) tocannabidivarin (CBDV), or THCV to THC. Certain specific ratios ofcannabinoids have been found to be clinically useful in the treatment ormanagement of specific diseases or medical conditions. In particular,certain of such formulations have been found to be particularly usefulin the field of pain relief and appetite stimulation.

It has particularly been observed by the present applicant thatcombinations of specific cannabinoids are more beneficial than any oneof the individual cannabinoids alone. Preferred embodiments are thoseformulations in which the amount of CBD is in a greater amount by weightthan the amount of THC. Such formulations are designated as“reverse-ratio” formulations and are novel and unusual since, in thevarious varieties of medicinal and recreational Cannabis plant availableworld-wide, CBD is the minor cannabinoid component compared to THC. Inother embodiments THC and CBD or THCV and CBDV are present inapproximately equal amounts or THC or THCV are the major component andmay be up to 95.5% of the total cannabinoids present.

Preferred formulations contain THC and CBD in defined ratios by weight.The most preferred formulations contain THC and CBD in a ratio by weightin the range from 0.9:1.1 to 1.1:0.9 THC:CBD, even more preferably theTHC:CBD ratio is substantially 1:1. Other preferred formulations containthe following ratios by weight of THC and CBD:—greater than or equal to19:1 THC:CBD, greater than or equal to 19:1 CBD:THC, 4.5:1 THC:CBD, 1:4THC:CBD and 1:2.7 THC:CBD. For formulations wherein the THC:CBD ratio issubstantially 1:1 it is preferred that the formulation includes about2.5 g/ml of each of THC and CBD.

Cannabis has been used medicinally for many years, and in Victoriantimes was a widely used component of prescription medicines. It was usedas a hypnotic sedative for the treatment of “hysteria, delirium,epilepsy, nervous insomnia, migraine, pain and dysmenorrhoea”. The useof cannabis continued until the middle of the twentieth century, and itsusefulness as a prescription medicine is now being re-evaluated. Thediscovery of specific cannabinoid receptors and new methods ofadministration have made it possible to extend the use of cannabis-basedmedicines to historic and novel indications.

The recreational use of cannabis prompted legislation which resulted inthe prohibition of its use. Historically, cannabis was regarded by manyphysicians as unique; having the ability to counteract pain resistant toopioid analgesics, in conditions such as spinal cord injury, and otherforms of neuropathic pain including pain and spasm in multiplesclerosis.

In the United States and Caribbean, cannabis grown for recreational usehas been selected so that it contains a high content oftetrahydrocannabinol (THC), at the expense of other cannabinoids. In theMerck Index (1996) other cannabinoids known to occur in cannabis such ascannabidiol and cannabinol were regarded as inactive substances.Although cannabidiol was formerly regarded as an inactive constituentthere is emerging evidence that it has pharmacological activity, whichis different from that of THC in several respects. The therapeuticeffects of cannabis cannot be satisfactorily explained just in terms ofone or the other “active” constituents.

It has been shown that tetrahydrocannabinol (THC) alone produces a lowerdegree of pain relief than the same quantity of THC given as an extractof cannabis. The pharmacological basis underlying this phenomenon hasbeen investigated. In some cases, THC and cannabidiol (CBD) havepharmacological properties of opposite effect in the same preclinicaltests, and the same effect in others. For example, in some clinicalstudies and from anecdotal reports there is a perception that CBDmodifies the psychoactive effects of THC. This spectrum of activity ofthe two cannabinoids may help to explain some of the therapeuticbenefits of cannabis grown in different regions of the world. It alsopoints to useful effects arising from combinations of THC and CBD. Thesehave been investigated by the applicant. Table 1 below shows thedifference in pharmacological properties of the two cannabinoids.

TABLE 1 Effect THC THCV CBD CBDV Reference CB₁ (Brain ++ ± Pertwee etal, receptors) 1998 CB₂ (Peripheral + − receptors) CNS EffectsAnticonvulsant † −− ++ Carlini et al, 1973 Antimetrazol − − GW DataAnti-electroshock − ++ GW data Muscle Relaxant −− ++ Petro, 1980Antinociceptive ++ + GW data Catalepsy ++ ++ GW data Psychoactive ++ −GW data Antipsychotic − ++ Zuardi et al, 1991 Neuroprotective + ++Hampson A J antioxidant activity* ++ − et al, 1998 Antiemetic + +Sedation (reduced ++ Zuardi et al, spontaneous activity) 1991 Appetitestimulation ++ Appetite suppression − ++ Anxiolytic GW dataCardiovascular Effects Bradycardia − + Smiley et al, 1976 Tachycardia +− Hypertension § + − Hypotension § − + Adams et al, 1977Anti-inflammatory ± ± Brown, 1998 Immunomoclulatory/ anti-inflammatoryactivity Raw Paw Oedema − ++ GW data Test Cox 1 GW data Cox 2 GW dataTNFα Antagonism + + ++ ++ Glaucoma ++ + *Effect is CB1 receptorindependent. † THC is pro convulsant § THC has a biphasic effect onblood pressure; in na

ve patients it may produce postural hypotension and it has also beenreported to produce hypertension on prolonged usage.

From these pharmacological characteristics and from direct experimentscarried out by the applicant it has been shown, surprisingly, thatcombinations of THC and CBD in varying proportions are particularlyuseful in the treatment of certain therapeutic conditions. It hasfurther been found clinically that the toxicity of a mixture of THC andCBD is less than that of THC alone.

Accordingly, the invention provides pharmaceutical formulations, havingall the essential features described above, which comprise cannabinoidsas the active agents and which have specific ratios of CBD to THC, whichhave been found to be clinically useful in the treatment or managementof specific diseases or medical conditions.

In a further aspect the invention also relates to pharmaceuticalformulations having all the essential features defined above, and whichhave specific ratios of tetrahydrocannabinovarin (THCV) orcannabidivarin (CBDV). THCV and CBDV (propyl analogues of THC and CBD,respectively) are known cannabinoids which are predominantly expressedin particular Cannabis plant varieties and it has been found that THCVhas qualitative advantageous properties compared with THC and CBDrespectively. Subjects taking THCV report that the mood enhancementproduced by THCV is less disturbing than that produced by THC. It alsoproduces a less severe hangover.

The invention still further relates to pharmaceutical formulations,having all the essential features as defined above, which have specificratios of THCV to THC. Such formulations have been found to beparticularly useful in the field of pain relief and appetitestimulation.

It has particularly been observed by the present applicants that thecombinations of the specific cannabinoids are more beneficial than anyone of the individual cannabinoids alone. Preferred embodiments arethose formulations in which the amount of CBD is in a greater amount byweight than the amount of THC. Such formulations are designated as“reverse-ratio” formulations and are novel and unusual since, in thevarious varieties of medicinal and recreational Cannabis plant availableworld-wide, CBD is the minor cannabinoid component compared to THC. Inother embodiments THC and CBD or THCV and CBDV are present inapproximately equal amounts or THC or THCV are the major component andmay be up to 95.5% of the total cannabinoids present.

Particularly preferred ratios of cannabinoids and the target medicalconditions for which they are suitable are shown in Table 2 below. Otherpreferred ratios of THC:CBD, THCV:CBDV and THC:TCHV and preferredtherapeutic uses of such formulations are set out in the accompanyingclaims.

TABLE 2 Target Therapeutic Groups for Different Ratios of CannabinoidProduct group Ratio THC:CBD Target Therapeutic Area High THC >95:5 Cancer pain, migraine, appetite stimulation Even ratio  50:50 Multiplesclerosis, spinal cord injury, peripheral neuropathy, other neurogenicpain. Reverse/Broad <25:75 Rheumatoid arthritis, Inflammatory ratio CBDbowel diseases. High CBD  <5:95 Psychotic disorders (schizophrenia),Epilepsy & movement disorders Stroke, head injury, Disease modificationin RA and other inflammatory conditions Appetite suppression

Formulations containing specific, defined ratios of cannabinoids may beformulated from pure cannabinoids in combination with pharmaceuticalcarriers and excipients which are well-known to those skilled in theart. Pharmaceutical grade “pure” cannabinoids may be purchased fromcommercial suppliers, for example CBD and THC can be purchased fromSigma-Aldrich Company Ltd, Fancy Road, Poole Dorset, BH12 4QH, or may bechemically synthesised. Alternatively, cannabinoids may be extractedfrom Cannabis plants using techniques well-known to those skilled in theart.

In preferred embodiments of the invention the formulations compriseextracts of one or more varieties of whole Cannabis plants, particularlyCannabis sativa, Cannabis indica or plants which are the result ofgenetic crosses, self-crosses or hybrids thereof. The precisecannabinoid content of any particular cannabis variety may bequalitatively and quantitatively determined using methods well known tothose skilled in the art, such as TLC or HPLC.

Thus, one may chose a Cannabis variety from which to prepare an extractwhich will produce the desired ratio of CBD to THC or CBDV to THCV orTHCV to THC. Alternatively, extracts from two of more differentvarieties may be mixed or blended to produce a material with thepreferred cannabinoid ratio for formulating into a pharmaceuticalformulation.

The preparation of convenient ratios of THC- and CBD-containingmedicines is made possible by the cultivation of specific chemovars ofcannabis. These chemovars (plants distinguished by the cannabinoidsproduced, rather than the morphological characteristics of the plant)can be been bred by a variety of plant breeding techniques which will befamiliar to a person skilled in the art. Propagation of the plants bycuttings for production material ensures that the genotype is fixed andthat each crop of plants contains the cannabinoids in substantially thesame ratio.

Furthermore, it has been found that by a process of horticulturalselection, other chemovars expressing their cannabinoid content aspredominantly tetrahydrocannabinovarin (THCV) or cannabidivarin (CBDV)can also be achieved.

Horticulturally, it is convenient to grow chemovars producing THC, THCV,CBD and CBDV as the predominant cannabinoid from cuttings. This ensuresthat the genotype in each crop is identical and the qualitativeformulation (the proportion of each cannabinoid in the biomass) is thesame. From these chemovars, extracts can be prepared by the similarmethod of extraction. Convenient methods of preparing primary extractsinclude maceration, percolation, extraction with solvents such as C1 toC5 alcohols (ethanol), Norflurane (HFA134a), HFA227 and liquid carbondioxide under pressure. The primary extract may be further purified forexample by supercritical or subcritical extraction, vaporisation andchromatography. When solvents such as those listed above are used, theresultant extract contains non-specific lipid-soluble material or“ballast”. This can be removed by a variety of processes includingchilling to −20° C. followed by filtration to remove waxy ballast,extraction with liquid carbon dioxide and by distillation. Preferredplant cultivation and extract preparation methods are shown in theExamples. The resulting extract is suitable for incorporation intopharmaceutical preparations.

There are a number of therapeutic conditions which may be treatedeffectively by cannabis, including, for example, cancer pain, migraine,appetite stimulation, multiple sclerosis, spinal cord injury, peripheralneuropathy, other neurogenic pain, rheumatoid arthritis, inflammatorybowel diseases, psychotic disorders (schizophrenia), epilepsy & movementdisorders, stroke, head injury, appetite suppression. The proportion ofdifferent cannabinoids in a given formulation determines the specifictherapeutic conditions which are best treated (as summarised in Table 2,and stated in the accompanying claims).

The principles of formulation suitable for administration of cannabisextracts and cannabinoids can also be applied to other medicaments suchas alkaloids, bases and acids. The requirements are that, if themedicament is insoluble in saliva, it should be solubilised and/orbrought into the appropriate unionised form by addition of bufferingsalts and pH adjustment.

Other lipophilic medicaments which may be included in the generalformulations of the invention may include, but are not limited to,morphine, pethidine, codeine, methadone, diamorphine, fentanyl,alfentanil, buprenorphine, temazepam, lipophilic analgesics and drugs ofabuse. The term “drugs of abuse” encompasses compounds which may producedependence in a human subject, typically such compounds will beanalgesics, usually opiates or synthetic derivatives thereof.

The formulation is preferably packaged in a glass vial. It is preferablyfilled to a slight over-pressure in an inert atmosphere e.g. nitrogen toprevent/slow oxidative breakdown of the cannabinoids, and is containedin a form such that ingress of light is prevented, thereby preventingphotochemical degradation of the cannabinoids. This is most effectivelyachieved using an amber vial, since the applicant has determined that itis UV and light in the blue spectrum, typically in the wavelength range200-500 nm, that is responsible for photodegradation.

The invention will be further described, by way of example only, withreference to the following experimental data and exemplary formulations,together with the accompanying Figures:

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1a and 1b illustrate mean plasma concentrations of cannabinoidsCBD, THC and 11-hydroxy THC following administration of high CBD (FIG.1a ) and high THC (FIG. 1b ) cannabis extracts to human subjects.

FIG. 2 illustrates mean plasma concentrations of cannabinoids CBD, THCand 11-hydroxy THC following administration of a cannabis extractcontaining a 1:1 ratio of THC:CBD to a human subject.

FIG. 3 illustrates cross-sectional area of aerosol plume vs % propyleneglycol in propylene glycol/ethanol liquid spray formulations.

FIG. 4 illustrates viscosity as a function of propylene glycol contentin propylene glycol/ethanol liquid spray formulations.

FIG. 5 illustrates cross-sectional area of aerosol plume vs viscosityfor propylene glycol/ethanol liquid spray formulations.

FIGS. 6 and 6 a show results of HPLC analysis of samples drawn fromstored, light exposed solutions of THC, before and after charcoaltreatment.

FIGS. 7 and 7 a show results of HPLC analysis of samples drawn fromstored, light exposed solutions of CBD, before and after charcoaltreatment.

FIG. 8 shows a summary of steps in production from seed accession todried Medicinal Cannabis.

FIG. 9 shows a flow chart of the process of manufacturing extract fromthe High-THC and High-CBD chemovars.

DETAILED DESCRIPTION OF THE INVENTION

Development of Pump-Action Spray Formulations

Initially the applicant looked at cannabinoid uptake in patients byapplying drops sublingually (BDS dissolved in a mixture of aglycerol/propylene glycol and ethanol) THC 5 mg/ml, CBD 5 mg/ml andTHC/CBD 5 mg/ml plus 5 mg/ml.

The results are noted in Table 3 below:

TABLE 3 Initial absorption: 20 min T max: approx 2 hours C max: 6 ng/mlTHC, 2 ng/ml CBD AUC 0-12: approx 16 ng · h/ml THC, 8 ng · h/ml CBDfollowing a dose of approx 20 mg of each cannabinoids Plasma levelsafter 6 hours were about 1 ng/ml THC and 0.5 ng/ml CBD

The proportion of 11 hydroxy tetrahydro cannabinol to THC (AUC 0-12) wasabout 1.9 indicating a significant amount of oral ingestion may haveoccurred.

On moving to a pump action sublingual spray (following problemssolubilising cannabinoids with hydroflurocabon propellant systems) theapplicant obtained the results noted in Table 4. The solvent systemcomprised 50:50 ethanol to propylene glycol (v/v ratio) with THC 25mg/ml; CBD 50 mg/ml and THC/CBD 25 mg/ml plus 50 mg/ml respectively.

TABLE 4 Initial absorption: 60 min T max: approx 3 hours C max: 6 ng/mlTHC, 8 ng/ml CBD AUC 0-12: approx 16 ng · h/ml THC, 22 ng · h/ml CBDfollowing a dose of approx 21 mg of THC and 35 mg CBD Plasma levelsafter 6 hours were about 1 ng/ml THC and 1 ng/ml CBD

The proportion of 11 hydroxy tetrahydro cannabinol to THC (AUC 0-12) wasabout 1.6. The profile for each cannabinoid was similar irrespective ofthe formulation (THC, CBD, THC plus CBD).

After accounting for the different dosages, whilst the extent ofabsorption was comparable to the drops, the rate of absorption wasslower and the proportion metabolised reduced.

Despite the slower rate of absorption the pump spray mechanism and theethanol/propylene glycol carrier system provided the opportunity toadminister sufficient cannabinoids, in a flexible dose form withaccuracy and advantageously with reduced metabolism.

The data obtained is illustrated in FIGS. 1a, 1b and 2, which show themean plasma concentrations for the formulations identified withreference to Tables 3 and 4.

That effective delivery of the cannabinoids can be achieved in a vehicleconsisting of ethanol and propylene glycol is illustrated by the plasmalevels shown in FIGS. 1a, 1b and 2. These show, respectively,formulations containing the high THC and high CBD formulations in FIGS.1a and 1b . Similarly, the effectiveness of a defined ratio formulationTHC:CBD 1:1 is illustrated in FIG. 2.

Significantly the ethanol/propylene glycol system was found to only workwith a pump action spray within quite narrow limits.

The findings giving rise to the development of pump spray formulations,as exemplified in formulations 1-4 below, are set out below:

Example 1—Significance of Particle Size

Applicant observed that the propellant aerosols that were developedsuffered from “bounce back” and this appeared to be a function ofdelivery speed and particle size.

Applicant determined that, in contrast to the propellant driven system,a pump spray could deliver an aerosol plume in which the particle sizecould be controlled to generate a particle size of between 20 and 40microns (thus maximising the amount of material hitting thesublingual/buccal mucosa and thus the amount of cannabinoids that can beabsorbed). To produce particles of the appropriate size the viscosity ofthe formulation needed to be carefully controlled. If the formulationwas too viscous droplet formation was hindered, a jet formed and thevalve blocked; If the formulation was not viscous enough they gotexcessive nebulisation, a plume of broad cross sectional area formed,and the spray was no longer directed solely onto the sublingual/buccalmucosa. This could result in the formulation pooling and some of theformulation being swallowed. In both cases the result is unsatisfactory.

In fact, it turned out that for the solvent of preferred choice,ethanol, and the co-solvent of preferred choice, propylene glycol, theworking range was fairly narrow as demonstrated below:

The viscosity of different combinations of ethanol/propylene glycol werestudied and their spray performance with a vp7/100 valve (Valois)compared. The results are tabulated in Table 5 below:

TABLE 5 Propylene Relative viscosity glycol/ethanol (run time in sec)Spray performance 100/0  442 Jet formed 80/20 160 Jet formed 60/40 80Some jetting 50/50 62 Good aerosol plume 40/60 44 Good aerosol plume20/80 26 Good aerosol plume  0/100 16 Good aerosol plume

From this data it appeared that addition of propylene glycol at greaterthan 60/40 would not be acceptable. These result, when read alongsideU.S. Pat. No. 3,560,625, could have suggested that the saidsolvent/co-solvent combination would be no good. However, applicantfound that patients could tolerate ethanol levels of this order whenpresented in the given formulations.

The effect of viscosity on aerosol plume was quantified by spraying thevarious formulations at a standard distance of 0.5 cm onto disclosingpaper. The distance represents the typical distance between the nozzleof the pump action spray unit and the sub lingual cavity in normal use.The paper was photocopied and the image of the plume excised and weighedto give a relative cross sectional area. The relative value was thenconverted into a real cross sectional area by dividing this value by theweight per cm² of the photocopier paper (determined by weighing a knownarea of paper). The results are given in Table 6 below:

TABLE 6 Area of cross section Propylene glycol/ethanol of spray plume100/0   3.5 cm² 80/20 14.2 cm² 60/40 17.9 cm² 50/50 20.7 cm² 40/60 29.4cm² 20/80 54.4 cm²  0/100 93.8 cm²This data is illustrated in FIG. 3.

Additionally plots of viscosity of mixtures of ethanol and propyleneglycol content FIG. 4 and plume cross section as a function of viscosityFIG. 5 are given.

The figures emphasise the dramatic and undesirable changes in propertieswhich occur outside the narrow range of ethanol/propylene glycol wt/wtof 60/40 and 40/60, and more particularly still 55/45 to 45/55, mostpreferably about 50/50.

Other factors are also significant in ensuring the combination is usedin a narrow range. Increasing the ethanol levels beyond 60 vol % givesrise to irritation and at propylene glycol levels approaching 60% and aslow as 55%, in the case of BDS, non polar derivatives present in the BDSbegin to precipitate out on prolonged ambient storage.

Other co-solvents which might be used would be expected to have similarlimitations. The more viscous the co-solvent the greater the problem ofproducing a plume forming spray, and the more polar, the greater therisk that precipitation will be exacerbated.

However, because the combination of ethanol/propylene glycol is able todissolve up to 50 mg/ml (i.e. therapeutically desirable levels ofcannabinoids), is non irritating, pharmaceutically acceptable, and thepropylene glycol also acts as a penetration enhancer maximisingbioavailability of the cannabinoids it is particularly advantageous.

The mean particle size of the preferred compositions have been shown tobe 33 μm when tested using a Malvern Marsteriser. The droplets, whichare considerably greater than 5 μm, therefore minimise the risk ofinhalation of aerosol.

Example 2—Effect of Water when the Cannabinoids are Present in a BDS

The presence of greater than 5% water in the formulation was shown tocause precipitation of the BDS as illustrated by the investigationdescribed in Table 7 below:

TABLE 7 Sequential addition of water was made to 5 ml 25 mg/ml THC and 5ml 25 mg/ml CBD in an ethanol/propylene glycol formulate (50/50). FinalApprox final solvent Vol of water vol ratio % vol Water/ added ml mlpropylene glycol/ethanol observation 0 5 0/50/50 Solution 0.05 5.051/49.5/49.5 Ppt forms but re dissolves on mixing 0.21 5.26 5/47.5/47.5Ppt forms. Solution remains cloudy after mixing

Indeed because of this observation the use of anhydrous ethanol ispreferred.

Example formulations (non-limiting) according to the invention are asfollows:

COMPOSITION 1 (General)

COMPONENT AMOUNT PER UNIT (1 ml) FUNCTION Active THC (BDS) 25-50 mg/mlActive CBD (BDS) 25-50 mg/ml Excipient Propylene Glycol 0.5 ml/ml Cosolvent Peppermint oil 0.0005 ml/ml Flavour Ethanol (anhydrous) qs to 1ml SolventCOMPOSITION 2 (High THC)

COMPONENT AMOUNT PER UNIT (1 ml) FUNCTION Active THC (BDS) 25 mg/mlActive Excipient Propylene Glycol 0.5 ml/ml Co solvent Peppermint oil0.0005 ml/ml Flavour Ethanol (anhydrous) qs to 1 ml SolventCOMPOSITION 3 (High CBD)

COMPONENT AMOUNT PER UNIT (1 ml) FUNCTION Active CBD (BDS) 25 mg/mlActive Excipient Propylene Glycol 0.5 ml/ml Co solvent Peppermint oil0.0005 ml/ml Flavour Ethanol (anhydrous) qs to 1 ml SolventCOMPOSITION 4 (THC/CBD Substantially 1:1)

COMPONENT AMOUNT PER UNIT (1 ml) FUNCTION Active THC (BDS) 25 mg/mlActive CBD (BDS) 25 mg/ml Active Excipient Propylene Glycol 0.5 ml/ml Cosolvent Peppermint oil 0.0005 ml/ml Flavour Ethanol (anhydrous) qs to 1ml Solvent

Example 3

The following example illustrates the application of liquid sprayformulations to the buccal mucosae and the blood levels produced bybuccal absorption in comparison with sublingual administration.

The following liquid formulations suitable for buccal administrationcontain self-emulsifying agents, and hence do not fall within the scopeof the present invention. Nevertheless, the general principlesillustrated by use of these compositions applies equally to the deliveryformulations according to the invention. Solutions were produced bydissolving (at a temperature not exceeding 50° C.) the followingingredients (quantitative details are expressed as parts by weight):—

A B C D E Glyceryl monostearate 2 — 2 — 2 (self-emulsifying) Glycerylmonooleate — 2 — 2 — (self-emulsifying) Cremophor RH40 20 30 30 20 30CBME-G1 to give THC 5 10 — — — CBME-G5 to give CBD — — 5 10 — CBME-G1and G5 to — — — — 10 each give THC & CBD α-Tocopherol 0.1 0.1 0.1 0.10.1 Ascorbyl palmitate 0.1 0.1 0.1 0.1 0.1 Ethanol BP to produce 100 100100 100 100

Cannabis Based Medicine Extract (CBME) is an extract of cannabis whichmay be prepared by, for example, percolation with liquid carbon dioxide,with the removal of ballast by cooling a concentrated ethanolic solutionto a temperature of −20° C. and removing precipitated inert plantconstituents by filtration or centrifugation.

The product formed by mixing these ingredients is dispensed in 6 mlquantities into a glass vial and closed with a pump action spray. Inuse, the dose is discharged through a break-up button or conventionaldesign. Proprietary devices that are suitable for this purpose are TypeVP7 produced by Valois, but similar designs are available from othermanufacturers. The vial may be enclosed in secondary packaging to allowthe spray to be directed to a particular area of buccal mucosa.Alternatively, a proprietary button with an extension may be used todirect the spray to a preferred area of buccal mucosa.

Each 1 ml of product contains 50-100 mg of Δ⁹-tetrahydrocannabinol (THC)and/or cannabidiol (CBD). Each actuation of the pump delivers a spraywhich can be directed to the buccal mucosae. In the above formulationsCBMEs of known cannabinoid strength are used. CBME-G1 is an extract froma high THC-yielding strain of cannabis, and CBME-G5 is from a highCBD-yielding variety. It will be clear to a person skilled in the artthat purified cannabinoids, and extracts containing the cannabinoids,can be made formulated as described above by quantitative adjustment.

Although solutions of CBME in ethanol alone can be used as a spray, thequantity of cannabinoid that can be delivered is limited by theaggressive nature of pure ethanol in high concentration as a solvent.This limits the amount that can be applied to the mucosae withoutproducing discomfort to the patient. When a group of patients receivedTHC or CBD in a solution of the type described above, directing thespray either sublingually or against the buccal mucosa, the patientsuniformly reported a stinging sensation with the sublingual application,but mild or no discomfort when the same solution was sprayed onto thebuccal mucosa. Spraying small quantities of this type of formulationonto the buccal mucosa does not appreciably stimulate the swallowingreflex. This provides greater dwell time for the formulation to be incontact with the buccal surface.

Formulations were administered to a group of 13 human subjects so thatthey received 4 mg THC, 4 mg of CBD or placebo (vehicle alone) via asublingual tablet, sublingual pump-action spray or buccal route.

Absorption [area under the absorption curve (AUC)] of cannabinoid andprimary metabolite were determined in samples of blood taken afterdosing. The following Table 8 gives these as normalised mean values.

TABLE 8 Route of Administration PAS sublingual Sublingual tabletOropharyngeal Analyte in Plasma AUC AUC AUC THC 2158.1 1648.4 1575 11-OHTHC 3097.6 3560.5 2601.1 CBD 912 886.1 858

These results show that the total amounts of cannabinoid absorbed bysublingual and buccal (oropharyngeal) routes are similar but that thereis a substantial (approximately 25%) reduction in the amount of11-hydroxy (11-OH) metabolite detected after oropharyngeal (buccal)administration. This finding is not inconsistent with reduced swallowing(and subsequent reduced hepatic) metabolism of the buccal formulation.

It is known that the 11-hydroxy metabolite of THC (11-OH THC) ispossibly more psychoactive than the parent compound. It is thereforedesirable to minimise the amount of this metabolite duringadministration, and this is likely to be achieved by using a formulationand method of application which reduces the amount of a buccal orsublingual dose that is swallowed. The pump action spray appears tooffer a simple means of reducing the amount of material that isswallowed and metabolised by absorption from the intestinal tract belowthe level of the oropharynx.

Example 4—Growing of Medicinal Cannabis

Plants are grown as clones from germinated seed, under glass at atemperature of 25° C.±1.5° C. for 3 weeks in 24 hour daylight; thiskeeps the plants in a vegetative state. Flowering is induced by exposureto 12 hour day length for 8-9 weeks.

No artificial pesticides, herbicides, insecticides or fumigants areused. Plants are grown organically, with biological control of insectpests.

The essential steps in production from seed accession to dried MedicinalCannabis are summarised in FIG. 8.

Example 5—Determination of Cannabinoid Content in Plants and Extracts

Identity by TLC

a) Materials and Methods

-   Equipment Application device capable of delivering an accurately    controlled volume of solution i.e., 1 μl capillary pipette or micro    liter syringe.    -   TLC development tank with lid    -   Hot air blower    -   Silica gel G TLC plates (SIL N-HR/UV254), 200 μm layer with        fluorescent indicator on polyester support.    -   Dipping tank for visualisation reagent.-   Mobile phase 80% petroleum ether 60:80/20% Diethyl ether.-   Visualisation reagent 0.1% w/v aqueous Fast Blue B (100 mg in 100 ml    de-ionised water). An optional method is to scan at UV 254 and 365    nm.    b) Sample Preparation    -   i) Herbal raw material    -   Approximately 200 mg of finely ground, dried cannabis is weighed        into a 10 ml volumetric flask. Make up to volume using        methanol:chloroform (9:1) extraction solvent.    -   Extract by ultrasound for 15 minutes. Decant supernatant and use        directly for chromatography.    -   ii) Herbal drug Extract    -   Approximately 50 mg of extract is weighed into a 25 ml        volumetric flask. Make up to volume using methanol solvent.        Shake vigorously to dissolve and then use directly for        chromatography.        c) Standards-   0.1 mg/ml delta-9-THC in methanol.-   0.1 mg/ml CBD in methanol.

The standard solutions are stored frozen at −20° C. between uses and areused for up to 12 months after initial preparation.

d) Test Solutions and Method

Apply to points separated by a minimum of 10 mm.

-   -   i) either 5 μl of herb extract or 1 μl of herbal extract        solution as appropriate,    -   ii) 10 μl of 0.1 mg/ml delta-9-THC in methanol standard        solution,    -   iii) 10 μl of 0.1 mg/ml CBD in methanol standard solution.    -   Elute the TLC plate through a distance of 8 cm, then remove the        plate. Allow solvent to evaporate from the plate and then repeat        the elution for a second time (double development).    -   The plate is briefly immersed in the Fast Blue B reagent until        the characteristic re/orange colour of cannabinoids begins to        develop. The plate is removed and allowed to dry under ambient        conditions in the dark.    -   A permanent record of the result is made either by reproduction        of the image by digital scanner (preferred option) or by noting        spot positions and colours on a tracing paper.        Assay THC, THCA, CBD, CBDA and CBN by HPLC        a) Materials and Methods

-   Equipment: HP 1100 HPLC with diode array detector and autosampler.    The equipment is set up and operated in accordance with in-house    standard operating procedures (SOPlab037)

-   HPLC column Discovery C8 5 μm, 15×0.46 cm plus Kingsorb ODS2    precolumn 5 μm 3×0.46 cm.

-   Mobile Phase Acetonotrile:methanol:0.25% aqueous acetic acid (16:7:6    by volume)

-   Column Operating 25° C.

-   Temperature

-   Flow Rate 1.0 ml/min

-   Injection Volume 10 μl

-   Run time 25 mins

-   Detection Neutral and acid cannabinoids 220 nm (band width 16 nm)    Reference wavelength 400 nm/bandwidth 16 nm    -   Slit 4 nm    -   Acid cannabinoids are routinely monitored at 310 nm (band width        16 nm) for qualitative confirmatory and identification purposes        only.

-   Data capture HP Chemistation with Version A7.01 software    b) Sample Preparation    -   Approximately 40 mg of Cannabis Based Medicinal Extract is        dissolved in 25 ml methanol and this solution is diluted to 1 to        10 in methanol. This dilution is used for chromatography.    -   0.5 ml of the fill solution, contained within the Pump Action        Sublingual Spray unit, is sampled by glass pipette. The solution        is diluted into a 25 ml flask and made to the mark with        methanol. 200 μl of this solution is diluted with 800 μl of        methanol.    -   Herb or resin samples are prepared by taking a 100 mg sample and        treating this with 5 or 10 ml of Methanol/Chloroform (9/1 w/v).        The dispersion is sonicated in a sealed tube for 10 minutes,        allowed to cool and an aliquot is centrifuged and suitably        diluted with methanol prior to chromatography.        c) Standards        External standardisation is used for this method. Dilution of        stock standards of THC, CBD and CBN in methanol or ethanol are        made to give final working standards of approximately accurately        0.1 mg/ml. The working standards are stored at −20° C. and are        used for up to 12 months after initial preparation.        Injection of each standard is made in triplicate prior to the        injection of any test solution. At suitable intervals during the        processing of test solutions, repeat injections of standards are        made. In the absence of reliable CBDA and THCA standards, these        compounds are analysed using respectively the CBD and THC        standard response factors.        The elution order has been determined as CBD, CBDA, CBN, THC and        THCA. Other cannabinoids are detected using this method and may        be identified and determined as necessary.        d) Test Solutions        Diluted test solutions are made up in methanol and should        contain analytes in the linear working range of 0.02-0.2 mg/ml.        e) Chromatography Acceptance Criteria:        The following acceptance criteria are applied to the results of        each sequence as they have been found to result in adequate        resolution of all analytes (including the two most closely        eluting analytes CBD and CBDA)    -   i) Retention time windows for each analyte:        -   CBD 5.4-5.9 minutes        -   CBN 7.9-8.7 minutes        -   THC 9.6-10.6 minutes    -   ii) Peak shape (symmetry factor according to BP method)        -   CBD <1.30        -   CBN <1.25        -   THC <1.35    -   iii) A number of modifications to the standard method have been        developed to deal with those samples which contain late eluting        impurity peaks e.g., method CBD2A extends the run time to 50        minutes. All solutions should be clarified by centrifugation        before being transferred into autosampler vials sealed with        teflon faced septum seal and cap.    -   iv) The precolumn is critical to the quality of the        chromatography and should be changed when the back pressure        rises above 71 bar and/or acceptance criteria regarding        retention time and resolution, fall outside their specified        limits.        f) Data Processing        Cannabinoids can be subdivided into neutral and acidic—the        qualitative identification can be performed using the DAD dual        wavelength mode. Acidic cannabinoids absorb strongly in the        region of 220 nm-310 nm. Neutral cannabinoids only absorb        strongly in the region of 220 nm.        Routinely, only the data recorded at 220 nm is used for        quantitative analysis.        The DAD can also be set up to take UV spectral scans of each        peak, which can then be stored in a spectral library and used        for identification purposes.        Data processing for quantitation utilises batch processing        software on the Hewlett Packard Chemstation.        a) Sample Chromatograms        HPLC sample chromatograms for THC and CBD Herbal Drug extracts        are provided in the accompanying Figures.

Example 6—Preparation of the Herbal Drug Extract

A flow chart showing the process of manufacture of extract from theHigh-THC and High-CBD chemovars is given in FIG. 9.

The resulting extract is referred to as a Cannabis Based MedicineExtract and is also classified as a Botanic Drug Substance, according tothe US Food and Drug Administration Guidance for Industry Botanical DrugProducts.

Example 7

High THC cannabis was grown under glass at a mean temperature of 21+2°C., RH 50-60%. Herb was harvested and dried at ambient room temperatureat a RH of 40-45% in the dark. When dry, the leaf and flower head werestripped from stem and this dried biomass is referred to as “medicinalcannabis”.

Medicinal cannabis was reduced to a coarse powder (particles passingthrough a 3 mm mesh) and packed into the chamber of a SupercriticalFluid Extractor. Packing density was 0.3 and liquid carbon dioxide at apressure of 600 bar was passed through the mass at a temperature of 35°C. Supercritical extraction is carried out for 4 hours and the extractwas recovered by stepwise decompression into a collection vessel. Theresulting green-brown oily resinous extract is further purified. Whendissolved in ethanol BP (2 parts) and subjected to a temperature of −20°C. for 24 hours a deposit (consisting of fat-soluble, waxy material) wasthrown out of solution and was removed by filtration. Solvent wasremoved at low pressure in a rotary evaporator. The resulting extract isa soft extract which contains approximately 60% THC and approximately 6%of other cannabinoids of which 1-2% is cannabidiol and the remainder isminor cannabinoids including cannabinol. Quantitative yield was 9% w/wbased on weight of dry medicinal cannabis.

A high CBD chemovar was similarly treated and yielded an extractcontaining approximately 60% CBD with up to 4% tetrahydrocannabinol,within a total of other cannabinoids of 6%. Extracts were made usingTHCV and CBDV chemovars using the general method described above.

A person skilled in the art will appreciate that other combinations oftemperature and pressure (e.g. in the range +10° C. to 35° C. and 60-600bar) can be used to prepare extracts under supercritical and subcriticalconditions.

Example 8—The Effects of Light on the Stability of the AlcoholicSolutions of THC, CBD or THCV

The following example includes data to support the packaging of liquiddosage forms in amber glass, to provide some protection from thedegradative effects of light on cannabinoids.

Further credence is also given to the selection of the lowest possiblestorage temperature for the solutions containing cannabinoid activeingredients.

Background and Overview:

Light is known to be an initiator of degradation reactions in manysubstances, including cannabinoids. This knowledge has been used in theselection of the packaging for liquid formulations, amber glass beingwidely used in pharmaceutical presentations as a light exclusivebarrier.

Experiments were set up to follow the effects of white light on thestability of methanolic solutions of THC, CBD or THCV. Followingpreliminary knowledge that light of different wavelengths may havediffering effects on compound stability (viz. tretinoin is stable onlyin red light or darkness), samples were wrapped in coloured acetatefilms or in light exclusive foil. A concurrent experiment used charcoaltreated CBME to study the effects of the removal of plant pigments onthe degradation process.

Materials and Methods:

Cannabinoids: 1 mg/ml solutions of CBME were made up in AR methanol.Methanolic solutions of CBME (100 mg/ml) were passed through charcoalcolumns (Biotage Flash 12AC 7.5 cm cartridges, b/no. 273012S) and werethen diluted to 1 mg/ml. Solutions were stored in soda-glass vials,which were tightly screw capped and oversealed with stretch film. Tubeswere wrapped in coloured acetate films as follows:

Red, Yellow, Green, and Cyan

Solutions were also filled into the amber glass U-save vials; these weresealed with a septum and oversealed. One tube of each series of sampleswas tightly wrapped in aluminium foil in order to completely excludelight. This served as a “dark” control to monitor the contribution ofambient temperature to the degradation behaviour. All of the above tubeswere placed in a box fitted with 2×40 watt white Osram fluorescenttubes. The walls of the box were lined with reflective foil and theinternal temperature was monitored at frequent intervals.

A further tube of each series was stored at −20° C. to act as a pseudoto the reference sample; in addition, one tube was exposed directly tolight without protection. Samples were withdrawn for chromatographicanalysis at intervals up to 112 days following the start of the study.The study was designated AS01201/AX282.

Samples of the test solutions were withdrawn and diluted as appropriatefor HPLC and TLC analysis. HPLC was carried out in accordance with TMGE.004.V1 (SOPam058). TLC was performed on layers on Silica gel (MNSilG/UV) in accordance with TM GE.002.V1 (SOPam056).

Two further TLC systems were utilised in order to separate degradationproducts:

a) SilG/UV, stationary phase, hexane/acetone 8/2 v/v mobile phase

b) RPC18 stationary phase, acetonitrile/methanol/0.25% aqueous aceticacid 16/7/6 by volume

Visualisation of cannabinoids was by Fast Blue B salt.

Results and Discussion:

HPLC Quantitative Analysis:

The results from the HPLC analysis of samples drawn from the stored,light exposed solutions, are plotted and presented as FIGS. 6 and 6 a(THC before and after charcoal treatment), and FIGS. 7 and 7 a (CBDbefore and after charcoal treatment).

It can be seen from FIGS. 6 and 6 a that there are significantimprovements to the stability of THC in all solutions, except thosestored in the dark (at ambient temperature) and at −20° C. (and hencewhich are not under photochemical stress). Even storage in amber glassshows an improvement when un-treated extract is compared with charcoaltreated extract. This, however, may reflect in an improvement of thethermal stability of the charcoal treated extract.

FIGS. 7 and 7 a present similar data for CBD containing extracts, fromwhich it can be seen that this cannabinoid is significantly moresensitive to the effects of light than is THC. In the absence ofcharcoal, all exposures, except in amber glass, light excluded (foil)and −20° storage, had degraded to non-detectable levels of CBD before 40days. This improved to figures of between 42 and 62 days followingcharcoal treatment. Amber glass protected CBD showed an improvement from˜38% residual compound at 112 days without charcoal clean up, toapproximately 64% at the same time after charcoal treatment. There wasalso an improvement in the stability of CBD in light excluded solutionafter charcoal treatment. This can only reflect a reduction in eitherthermo-oxidative degradation, or a residual photochemical degradationinitiated by light (and/or air) during CBME and solution preparation.

Thin Layer Chromatography Qualitative Analysis:

The evaluation of the light degraded solutions using thin layerchromatography, used both the existing normal phase system (i.e. Silicastationary phase and hexane/diethyl ether as mobile phase) and twoadditional systems, capable of resolving more polar or polymericproducts formed during the degradation processes.

Thus, chromatography using the hexane/diethyl ether system, showed thatfor THC by day 112, there was a reduction in the intensity of the THCand secondary CBD spots with all of the colour filtered lights (data notshown). At the same time, there was an increase in the intensity of FastBlue B staining material running at, or close to, the origin. Foilprotected solution exhibited none of these effects.

CONCLUSIONS AND RECOMMENDATIONS

Cannabinoids are known to be degraded by a number of natural challenges,viz. light, heat, oxygen, enzymes etc. It is most likely that in anextract of herbal plant material, which has not been subjected toextensive clean-up procedures, that some of these processes may still beable to continue. Paradoxically, it is also likely that the removal ofcannabinoids from the presence of any protection agents within the planttissue, may render the extract more likely to suffer from particulardegradation pathways.

Packaging into amber glass vials, conducting formulation manufacture inamber filtered light, and the storage of plant extracts andpharmaceutical formulations at temperatures as low as possiblecompatible with manufacturing and distribution requirements and patientcompliance eliminates, or at least reduces, the effect of light ondegradation of cannabinoids. These actions dramatically improved thestorage stability of both plant extracts and finished products.

It was interesting to note that CBD appeared to be markedly less stablethan THC, when subjected to photochemical stress. This is the oppositeof the finding for the relative thermo-oxidative stabilities, in whichTHC is the less stable. This seems to indicate that, although polymericdegradation products may be the common result of both photochemical andthermo-oxidative degradation, the exact details of the mechanism are notidentical for the two processes.

Among the conclusions that can be drawn are the following:

1] The choice of amber glass for the packaging of the dose solutionsprovides improved stability, but minor improvements can be made byadditional light exclusion measures.

2] The drying process and subsequent extraction and formulation ofcannabis extracts should indeed be carried out in low intensity, amberfiltered light.

3] Consideration should be given to the blanketing of extracts under aninert atmosphere (e.g. Nitrogen).

4] Clean-up of cannabis extracts by simple charcoal filtration afterwinterisation, may yield substantial improvements to product shelf-life.

Those skilled in the art will recognize, or be able to ascertain usingno more than routine experimentation, many equivalents to the specificembodiments of the invention described herein. Such equivalents areintended to be encompassed by the following claims.

All references disclosed herein are incorporated by reference in theirentirety.

The invention claimed is:
 1. A cannabinoid containing pharmaceuticalformulation, wherein the formulation comprises one or more cannabinoidsand one or more pharmaceutically acceptable excipients is packaged inpackaging to improve storage stability by protecting the formulationfrom the degradation by light, wherein the packaging comprises alight-excluding foil, and wherein the pharmaceutical formulationcomprises an alcoholic solvent.
 2. The cannabinoid containingpharmaceutical formulation as claimed in claim 1, wherein theformulation comprises one or more of the cannabinoids selected fromtetrahydrocannabinol (THC), cannabidiol (CBD), tetrahydrocannabivarin(THCV) and cannabidivarin (CBDV).
 3. The cannabinoid containingpharmaceutical formulation as claimed in claim 2, wherein theformulation comprises cannabidiol (CBD).
 4. The cannabinoid containingpharmaceutical formulation as claimed in claim 1, wherein theformulation is packaged so as to prevent ingress of light.
 5. Thecannabinoid containing pharmaceutical formulation as claimed in claim 1,wherein the formulation is packaged to exclude UV light and/or lightfrom the blue region of the spectrum.
 6. The cannabinoid containingpharmaceutical formulation as claimed in claim 5, wherein theformulation is packaged to exclude the wavelength of light between 200and 500 nm.
 7. The cannabinoid containing pharmaceutical formulation asclaimed in claim 1, wherein the cannabinoid is present as an extract ora highly purified Pharmacopeial grade substance.
 8. The cannabinoidcontaining pharmaceutical formulation as claimed in claim 1, wherein theformulation is further packaged in or under an inert atmosphere.
 9. Thecannabinoid containing pharmaceutical formulation as claimed in claim 8,wherein the inert atmosphere is nitrogen.
 10. A method of improvingstorage stability of a cannabinoid containing pharmaceutical formulationcomprising packaging the formulation comprising one or more cannabinoidsand one or more pharmaceutically acceptable excipients in packaging toprotect it from degradation by light, wherein the packaging comprises alight-excluding foil, and wherein the pharmaceutical formulationcomprises an alcoholic solvent.
 11. The method as claimed in claim 10,wherein the pharmaceutical formulation comprises one or more of thecannabinoids selected from tetrahydrocannabinol (THC), cannabidiol(CBD), tetrahydrocannabivarin (THCV) and cannabidivarin (CBDV).
 12. Themethod as claimed in claim 11, wherein the pharmaceutical formulationcomprises cannabidiol (CBD).
 13. The method as claimed in claim 10,wherein the pharmaceutical formulation is packaged so as to preventingress of light.
 14. The method as claimed in claim 10, wherein thepharmaceutical formulation is packaged to exclude UV light and/or lightfrom the blue region of the spectrum.
 15. The method as claimed in claim10, wherein the cannabinoid is present as an extract or a highlypurified pharmaceutical grade substance.
 16. The method as claimed inclaim 10, wherein the pharmaceutical formulation is packaged in or underan inert atmosphere.